As fuel economy becomes paramount in the transportation industry, efforts have increased to achieve higher internal combustion (IC) engine efficiencies and to seek alternative powertrains. Coolant valves are well known and can be arranged to provide coolant flow control for temperature management of various powertrain components including internal combustion engines, transmissions and various components of hybrid electric and fuel cell vehicles.
A portion of coolant valves are electro-mechanical in design, incorporating an actuator assembly that interfaces with a mechanical rotary valve body to provide a controlled flow of coolant to a selected powertrain component or system. An electric motor, controlled by the engine control unit, is often employed within the actuator assembly of the electro-mechanical rotary valve (EMRV) to achieve any desired angular position of the rotary valve body. A transmission or gear train can be utilized between the electric motor and rotary valve body. An injection molded plastic outer housing is typically used for an EMRV that is often mounted directly on either a cylinder head or cylinder block of the IC engine. The use of plastic provides a light-weight solution to fulfill complex outer housing design specifications that are required for mounting and sealing the EMRV to the engine, providing connections for hoses, and guiding and sealing the internal rotary valve. The outer housing must be able to withstand the rigors of a vibrating IC engine, which include large temperature fluctuations and exposure to dust, water, and salt. Additionally, all of the fasteners for either mounting or sealing of the hoses must be accessible within a crowded IC engine compartment.
Due to these design requirements and rigorous environment, the outer housing is often one of the higher priced components of the EMRV and also contributes to many failure modes that could occur. Amongst all of the components of the EMRV, the outer housing typically requires the most time and effort to achieve a production-worthy design. A new design for an EMRV is needed that addresses these shortcomings while maintaining critical functions for current and future applications.